Question

The sodium metal is represented by ‘Na'. Its atomic number is:

• A. 12
• B. 11
• C. 14
• D. 13

Hint:

Sodium has symbol \(Na\) and atomic number \(11\). Its electronic configuration is \(2,8,1\).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:

• This chemistry question asks for the atomic number of the metal sodium, which is represented by the chemical symbol 'Na'.

• We need to identify its position and number of protons in the periodic table.

Step 2: Detailed Explanation:

• The atomic number of an element is defined as the total number of protons present in the nucleus of an atom of that element. It determines the element's position on the periodic table.

• Sodium is a highly reactive alkali metal belonging to Group 1 and Period 3 of the periodic table. Its chemical symbol 'Na' comes from its Latin name, Natrium.

• A neutral sodium atom has 11 protons and 11 electrons, giving it an atomic number of 11. Its electronic configuration is:
\[ 1s^2 2s^2 2p^6 3s^1 \]

• Let us review the atomic numbers of neighboring elements:

• Atomic number 11: Sodium (Na)

• Atomic number 12: Magnesium (Mg) (Option A)

• Atomic number 13: Aluminum (Al) (Option D)

• Atomic number 14: Silicon (Si) (Option C)

• Therefore, the atomic number of sodium is 11, which corresponds to Option (B).

Step 3: Final Answer:
The correct option is (B).